Connecting the Swing Bridge to my Bronx Terminal Layout

You don’t normally connect something to your layout – you build it for your layout so that it fits! That’s not how it worked this time for the swing bridge segment of my Third Avenue Bridge, however. First of all, it was mostly outside of my original layout. Second, with a pre-pandemic plan to move out of our current apartment, my Bronx Terminal layout was wrapped in Saran wrap in our basement storage. And there was always a big question mark about the bridge’s width. How would the bridge with its 17 cm wide deck would connect to the 14 cm wide girder bridge that spans the river between the Bronx-side abutment and the rest pier? I knew something was wrong there.

The Plan

In anticipation of some design issues, I already had rebuilt the center segment of the swing bridge by reducing its width from 5 to 4 cm. All three segments would now be equally wide. This would give me a 17cm wide bridge including the walkways. It would match pretty well the 89 ft that I measured based on a plan (photo WSM_s_0378 in the NYC Dept of Records photo archive). As a result, there would be no space for the TARS double track. Since the bridge only had westbound traffic for a long time and I only modeled one track anyway, that was not an issue. (I was wondering, though, how they crammed two tracks and four lanes into those 89 ft width). I finally managed to locate all the existing bridge pieces in boxes in the basement. Lining them up and comparing them to an aerial photo, I immediately realized what the problem was.

When I built the girder bridge that attaches to the bridge abutment, I used the width of the access ramp instead of extending it. That way it matched the width of the abutment – something that was logical. The aerial photo shows, however, that the width of the driveway gradually increases while the bridge’s width remains constant. The wider driveway came at the cost of the sidewalk.

Consequently, to connect the swing bridge to the layout, I’d have to make a few changes. First, I’d have to remove the small walls on the abutment so that the girder bridge can connect to the full width. Second, I’d have to extend the girder bridge width for its full length to match the abutment. Third, I’d adjust the separation between sidewalk and driveway. The driveways will then match the wider width on the rest pier. And at last, I needed to extend the rest pier by more than half an inch on each side.

I realized that to make these changes, I needed a solid base on which I could place and mount them. With my layout tucked away in the basement, I decided to take a fresh start by building a small diorama. I wouldn’t need to glue everything down so that I could always reuse the individual structures on the original layout.

Diorama Base

A frame of 1×2 strip board 40″ long and 12″ wide serves as the diorama’s under frame. The diorama covers the Harlem River and a small part of the river bank on the South Bronx side. This is big enough for the swing bridge, its rest piers, the girder bridge and the abutment on the Bronx side. I’d have to add the central bridge pier and the wooden fender. I’d also add a few distinctive elements of the CNJ Bronx Terminal and its surroundings. Apart from the bridge abutment I’ll add the engine shed that housed the famous CNJ #1000 60 ton switcher. Due to the complex connection to the terminal’s outer circular loop, I never included that one on my layout. With this diorama I can now make good on my original omission. Plus, I could practice once again pouring resin into the river. My first attempt on the layout yielded mixed results, to say the least.

Bridge Piers

Integrating everything on a Diorama forced me to deal with some details I generously passed over on my layout. How to connect the roadways on the bridge deck to the rest pier and girder bridge? First. I had to make sure that the swing bridge leveled perfectly with the deck of the girder bridge. Second, I developed a complementary connection piece that sits on the rest pier. It closes the gap between the round edge of the bridge deck and the girder deck. But it also ensures that the bridges closes smoothly when it moves back into the closed position. In reality, it would also have to help carrying the weight of the bridge when closed – not a problem in the case of a model. I chose to use three mini roller bearings to minimize resistance (see photo below).

Pedestrian Shelter

One of the huge benefits of having a laser cutter and engraver is the almost limitless design capabilities for structures. Not being bound to a manufacturer of a model that looks close enough to a prototype is a blessing. This is especially true for accessories of structures that are specific to a particular location. Since I have started modeling the CNJ Bronx Terminal, I’ve always had a checklist in the back of my brain with items that I have not seen in all the online stores for railroad models. The pedestrian shelter and the adjacent little hut for a bridge guard were definitely on that list.

No longer – it took me a few hours to draw them in Inkscape based on photos and have them cut by the laser cutter mostly out of laser board. Assembling, painting and weathering was done in little time. I estimated the measures for the structure and wasn’t too concerned if the result wasn’t a 100% copy of the prototype. It was close enough anyway. There are two pairs of shelters and bridge guard huts: One on each side of the girder bridge deck close to the rest pier. I’d only have to take care of the pair on the Bronx side but there’s also one on the Harlem side.

Each of the shelters has a little sibling next to it. That little hut must have been the bridge guard’s house. Its architecture is not very demanding apart from the wicked geometry of the dutch gable roof. But the challenge of this structure lies in its tiny size. The walls are slightly more than half an inch long. The windows measure about 3.5×5 mm with 4 panes resulting in mullions that are about 1/3 mm thin. I laser-cut the two layers of the structure out of .011″ laser board. Assembling the kit of unusually small parts was tedious work and I had to go through several iterations until I was happy with the result. I also tested a version with small .02x.04″ painted and weathered lumber. The result was not convincing, so I stayed with the laser board-only construction.

Center Pier with Fender

Who would ever want to model a fender of a swing bridge? Well, as I was modeling the immediate perimeter around the bridge with my diorama, I had to deal with it. No matter how much it was a distraction from the main subject or how much I disliked it. The bridge fender serves as protection for the central pier against errant vessels on the Harlem River. It also protects the pier against lateral static pressure from the ice sheet in winter when the Harlem River is frozen (which can still happen). So it is still part of the bridge. Note that the walls of the fender are not watertight. There is water inside the fender and on the same level as in the river.

The central pier fender has almost the same size as the Third Avenue Bridge except it is perpendicular to it. It has to be slightly wider than the base of the bridge on the central pier. It also has to be at least as long as the length of the bridge since it must protect it in the open position. Its shape is a hexagon diamond, well visible on aerial photos of the first half of the twentieth century. On top of each end, a massive trestle supports the bridge deck in open position.

Based on the photographic material we can conclude that the new fender was similar to the old one. (The old fender was destroyed by a fire in 1999). Both show that a series of wooden trusses carry the walls. At their edges they are also anchored in the underground by a system of piles. The interlocked lateral and longitudinal trusses or frames are arranged in equidistant intervals. When looked down from above on Google Maps, they form a checkerboard-like structure.

I decided to stick to the current version. Even though the truss work looks more convoluted, it follows a clear design and is easier to replicate in a model. I needed a base plate of the fenders overall shape. Built on the base, I’d add lateral trusses about every 12′ (about 7/8″ in N scale) and longitudinal frames in the same interval. The longitudinal frames would be slightly smaller and with notches so I could introduce them in the larger lateral frames. There’s a second type of longitudinal frame about half the height of the full frame. Plus there are diagonal members that are part of the lateral trusses. I’d have to add them separately as individual beams. On top, a system of catwalks along the edge of and across the fender complete the construction. The base, trusses and frames and the top frame for the walkways are all made of 1/16″ MDF and cut on the laser. For the additional diagonal beams and the fender wall I used scale lumber.

CNJ Bronx Terminal Engine House

The Engine House is a relatively small structure. It had to house the 60-ton diesel Boxcab CNJ #1000 which had a length of 30 ft, and a width of slightly less than 10 ft. It was about 13 ft high (an archive photo from 1914 shows that the structure existed before CNJ #1000 was acquired). The measures I could read from a map are 39 ft length and about 22 ft width. Given the limitations of the Bronx Terminal perimeter, the Engine House is almost entirely built on piles driven into the riverbed of the Harlem River. The appearance of the structure – corrugated white walls with a very particular outside (most likely wooden) frame – is similar to the round freight house of the CNJ Bronx Terminal.

Fortunately, there is good photographic material available, at least from viewspoints across the Harlem River. It was relatively easy to figure out how to build the platform of the structure. And it was a pleasure to build it with dowels and scale lumber, and to paint and weather to give it a good prototypical look. The house I built in two layers. An inner shell with the windows is laser cut from laser board. The outer layer is a shell made of 1 mm wooden planks styrene sheet that emulates well the corrugated surface of the prototype. The outside trimming I cut again with thin laser board. I couldn’t find any photos of the front with the door for the engine so I had to design one by myself. It has two wings and a round top and almost fills out completely the front wall. A small door within the big door allows staff to enter and exit the building.

CNJ Bronx Terminal Tracks

When I decided to include the CNJ engine house on my bridge diorama my initial plan was to keep track work at a minimum. Maybe the track leading from the outer cyclic track to the engine house would be enough. After all, (re-)modeling the CNJ Bronx Terminal wasn’t my goal here. But then the plan kept growing, I certainly would also have to add the track leading to the other side of the bridge to the CNJ Bronx Terminal extension on 135th Street. I ended up drawing all the tracks that the prototype had in that small 8″x4″ section. I only left out one track that would have made the track work unnecessarily complex. This was the connection between the extension track under the arch to inner track of the transfer bridge.

I knew what to expect – I had constructed that section four years earlier when I built the Bronx Terminal layout. I’d have to build a 90 degree crossover and a double diamond crossover on curved track. Plus a curved turnout. I also decided to make it in code 40 this time. I had one big additional help this time – my laser cutter. Using my existing plans, I drew the track details in Inkscape so I could engrave and cut a jig for the rails, guard-rails and ties. To help with the crossovers, I also engraved a reverse jig just for the rails.

I had never worked before with code 40 so I was a bit worried that my undertaking would not succeed. It turned out to be much easier than I thought. In fact, having completed the tracks now, I found it even easier than code 55. Yes, you have to be more careful when milling the foot, the web or the head of the rail for the crossovers. But the jigs helped me immensely with the milling. For the material and tooling, I used mostly Fasttrack products that I worked with before. For the rails I used used MicroEngineering’s code 40 unweathered product. Another tool that helped me this time was Fasttrack’s Gapster, a very practical aid for filing the gaps on PCB ties.

I made one big simplification that saved me a lot of time and hassles: I decided to make the tracks mechanically functional but not electrically operational. This meant I did not have to cut insulation gaps into the rails. For a single crossover, that’s 12 (8+4) cuts and the cuts would have to include both the rail and the guardrail. PCB tie placement becomes far more complicated when gaps have to be cut to ensure sufficient stability. Not this time! After a few evenings and two weekends of cutting, milling, filing, soldering and filing again, I had my section of track completed. Painting, weathering and ballasting was done quickly for that small area.

The result looked good. I felt for the first time that the code 40 looked prototypical in N scale. Code 40 translates to a prototypical height of about 6 1/2″ which is somewhere between the lighter 100 lb/yd and the heavier 120 lb/yd rail in North America.

Pouring the River

I finally got to the point where I no longer could defer the pouring of the water in my Harlem River. My first application of epoxy resins to emulate a water surface on my CNJ Bronx Terminal layout wasn’t exactly a success. I was unsure about which product to use. I briefly considered the Deep Pour Water product from Woodland Scenics but then went with Envirotex Lite. That one seemed to be simpler to use and more robust, plus it had good reviews. Also, the circumstances were more favorable this time. That painful experience on my layout happened during a typical sticky New York Summer in July. High relative humidly at around 90F outside with the A/C running all day. It is end of March now, the temperatures still around 50F or lower and humidity way below 50%.

I still had challenges, though. The fender separated the eastern from the western part of the river and it also had to be flooded. I absolutely wanted a properly leveled surface across the entire diorama. The only way I could achieve this would be by pouring the water first without the fender in place. Once I had poured the first layer, I’d have to carefully put it in place. The engine house platform on wooden piles was a different story. The structure had some beams on the inside to keep the piles in place and to reinforce the structure. To ensure that all of it was properly covered with water I had to cut 1/8″ wide gaps at several locations without compromising the structure’s stability. Since I could glue it down to the bottom of the river now, that wasn’t really a problem.

Once all was ready, I mixed the resin with the hardener, carefully following instructions. I then added the Woodland Scenics Murky Water Tint to get the desired coloration of the Hudson River water. This product was considered to be compatible with the Envirotex resin in reviews. In retrospect, I could have used a bit more to get a more murky effect. The Envirotex Lite resin is thicker than other products but it still flows sufficiently well into all corners when enough resin is used. The recommendation is to pour layers of 1/8″. I needed at least that depth but wanted a little more, maybe 3/16″. Once I had the 1/8″ poured, I placed the fender around the center pier walls. I put weights on top to ensure that it would not float and change its position.

All worked well as planned, I did not notice any heat from the chemical reaction nor had I to deal with an excessive amount of bubbles. The resin was hard enough after about 24 hours. I decided, however, that the water level was high enough and called it a pour. The capillary effect of the epoxy resin leads to a water line that is at least 1 mm higher where it touches the walls. And given the viscosity of the product, I’d have to pour at least another 1/8″ – too much anyway. I was happy with the water feature on my diorama and was looking forward to wrapping up this project.